The amount of data that is being managed by companies continues to increase pursuant to the advancement of information society in recent years. Moreover, recently, the types of data are also increasing in addition to the increase in the amount of data, and such increase in the types of data is making data management in companies even more difficult.
Today, as the types of data that are being managed by companies, there are DB (database) data, document data and the like. Here, an application (DB) in the host computer that uses the DB data has a data management function of managing what kind of data is written in which location of which data storage area. Thus, the data management function that is demanded in a storage apparatus is relatively simple regarding the DB data. However, a storage apparatus is demanded of high performance regarding the data access performance such as having a short response time. Meanwhile, a document creation application in a host computer that uses the document data is only loaded with a limited data management function in light of the attribute of such application. Thus, the storage apparatus-side needs to provide the data management function for the document data.
Accordingly, since the requirements that are demanded in a storage apparatus differ depending on the type of data, the current situation is that companies and the like that use a large-scale data center use both a block storage apparatus and a file storage apparatus as storage apparatuses based on the efficient allocation of resources.
Here, a block storage apparatus is a storage apparatus for providing a data access means based on a block access interface such as a fibre channel (Fibre Channel) or an iSCSI (Internet Small Computer System Interface) and, typically, a host computer performs data access in a manner that is compliant with the SCSI standard. Specifically, a block storage apparatus provides a storage area as a volume, and a host computer designates the storage of the data read/write destination based on the ID of the volume (volume ID) and the LBA (Logical Block Address) that shows the location in that volume.
With a block storage apparatus, in many cases, the respective volumes are configured from a plurality of physical disks for the purpose of fault tolerance and performance improvement. Today, as the foregoing physical disk, various types of storage devices are being used; for instance, SSD (Solid State Disk) or SATA (Serial Advanced Technology Attachment) disk drives, SAS (Serial Attached SCSI) disk drives and the like. Since an SSD yields high performance in comparison to a case of using a SATA disk drive or a SAS disk drive, the volumes that are configured from such SSD are able to yield high performance in comparison to the volumes that are configured from a SATA disk or a SAS disk drive. Nevertheless, an SSD is more expensive in comparison to a SATA disk drive or a SAS disk drive, and the cost of volumes will also increase.
Moreover, recent block storage apparatuses are able to provide, in addition to logical volumes based on conventional RAID (Redundant Array of Inexpensive Disks) technology, virtual volumes based on the Thin Provisioning technology. A virtual volume does not have the substance of a storage area at the point in time that a volume is created and allocated to a host computer, and is a volume to which a storage area (hereinafter referred to as the “real storage area”) provided by a physical disk is provided only when data is written from the host computer into the virtual volume. As a result of using a virtual volume, the capacity of a physical disk can be effectively utilized since the real storage area of a physical disk is only allocated to the location in the volume where data is actually written.
Meanwhile, a file storage apparatus is a storage apparatus for providing a data access means based on a file access interface such as an NFS (Network File System) or a CIFS (Common Internet File System). A file storage apparatus typically provides a real storage area as a file system. A host computer or an application running thereon may freely create files, which are data blocks, in a file system if authorized to do so, and may freely assign a name (file name) according to given rules. When a host computer is to access data, it may do so by designating the file name (file path), and there is no need for the host computer-side to manage in which address within the file system data is being stored. Moreover, the host computer is able to create a directory in the file system and collectively store related files therein, and additionally use functions for facilitating data management such as by referring to attribute information (metadata); for instance, file creation date/time, file update date/time and the like.
Moreover, in recent years, provided is a file storage apparatus for providing a file access interface based on XAM (eXtensible Access Method). As a result of using a file access interface based on XAM, the host computer can freely define the metadata of the respective files and use the same for data management, and thereby further facilitate data management. Thus, XAM is particularly used in the long-term storage of data.
Further, a file storage apparatus can be broadly classified into a stand-alone type and a gateway type. While the stand-alone type retains the physical disks on its own, the gateway type does not retain the physical disks or, even if it does, only retains physical disks of a limited capacity that are used for storing micro programs and management information, and adopts a mode of using the volumes provided by the other block storage apparatuses as the data storage area. Thus, a gateway type is able to allocate the physical disks or volumes that were being used for the block access interface to a file storage apparatus and divert them to the use for the file access interface, and the opposite diversion is also possible. Meanwhile, since a stand-alone type retains physical disks for exclusive use by the file storage apparatus, it is difficult to divert such physical disks to other uses. Thus, companies that use a large-scale data center often use the gateway type.
Incidentally, as inventions relating to a computer system, PCT (WO) 2005-535961 (Patent Document 1) discloses an invention relating to a multi-protocol storage appliance for supporting a file protocol and a block protocol. In addition, Japanese Published Unexamined Application No. 2003-345631 (Patent Document 2) discloses an invention relating to a computer in which different types of storage apparatuses coexist, wherein a host computer uses the storage apparatuses according to the characteristics of the individual storage apparatuses, and Japanese Published Unexamined Application No. 2005-275526 (Patent Document 3) discloses an invention for selecting the storage destination of data according to the usage thereof and thereby allocating the storage area.